The present invention generally relates to a wheel suspension; and more particularly to a wheel suspension with a coil spring which is arranged separately from a spring strut, has a free space for a drive shaft, and ensures an optimal guiding of the coil spring.
A wheel suspension is disclosed by German Patent Specification (DE-PS) 34 05 174 in which a coil spring is supported separately from a shock absorber on a wheel guiding link. The coil spring extends into a plane below a wheel drive shaft in which the wheel guiding link is pivoted on a wheel carrier. In order for the coil spring to be arranged without any contact with the drive shaft guided through transversely with respect to the wheel, it has a joining piece in this area which is free of windings. This joining piece connects the upper spring part with the lower spring part and makes it possible for the drive shaft to extend through the enveloping cylinder of the coil spring. In this type of a construction, the lower spring pad fastened to the link always takes up the angle of inclination of the link which may result in a buckling of the coil spring.
It is an object of the present invention to provide a wheel suspension with a coil spring which is arranged separately from a spring strut, has a free space for a drive shaft, and ensures an optimal guiding of the coil spring.
Principal advantages achieved by preferred embodiments of the invention are that, in the case of a double-wishbone axle, despite a coil spring which is arranged separately from a spring strut and which, above a wheel drive shaft, is supported on a guiding element, a relatively large shock absorber ratio is achieved. By means of the auxiliary construction of a guided lower spring plate, the coil spring may be arranged separately which is utilized for the increase of the damper ratio.
In order to avoid a buckling or a snapping of the unguided coil spring in the extreme positions, the coil spring according to preferred embodiments of the invention is advantageously supported on spring plate rotatably disposed at the lower wishbone. In addition, this spring plate is guided by means of an auxiliary control arm which, if it is arranged in parallel to the lower wishbone, ensures an approximately parallel guiding of the lower spring plate with respect to the upper spring pad, so that a buckling of the coil spring is avoided.
In addition to these advantages, it is achieved by means of the guiding element connected with the wishbone that the drive shafts led to the wheels can extend free of the coil spring without contacting them even under extreme driving conditions. For this purpose, the guiding element is equipped with an approximately vertically aligned stem which is passed by the drive shaft.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.